Reliability in making emergency calls is an important feature of any phone service. In the United States, emergency calls are handled through the 9-1-1 system, which originated in the era of landline telephones. The 9-1-1 system originally relied on the assumption that each phone is permanently present at a specific geographical location (e.g., a residential or business street address). The subsequent development of mobile calling devices has created technical hurdles to emergency calling. Because a mobile calling device can potentially make emergency calls from any location within a vast geographical area (e.g., at least the entire United States), additional steps beyond the connection of an emergency call itself are necessary to ensure that emergency services can be accurately dispatched to a caller's location.
Emergency services can be dispatched in response to an emergency call. A caller can initiate an emergency call (e.g., from a landline telephone, mobile phone, or other calling device) by dialing an emergency number (e.g., 9-1-1 in the United States). The emergency number connects the caller to an appropriate public-safety answering point (“PSAP”) (e.g., a 9-1-1 dispatch center). The PSAP is selected on the basis of the caller's geographical location, as explained in more detail below. The caller is connected to an operator at the PSAP. Upon determining the nature of the emergency call, the operator dispatches appropriate emergency services to the caller's location if an emergency that requires a response by emergency services actually exists.
The selection of an appropriate PSAP is crucial because each PSAP is responsible for dispatching emergency services within a specific geographical area (e.g., a city or county), and a given PSAP can only directly dispatch emergency services to locations within its specific geographical area. When routing an emergency call to a PSAP, it is therefore essential that the selected PSAP is one whose geographical area of responsibility includes the caller's current location. Therefore, selecting an appropriate PSAP requires ascertaining the caller's geographical location. If a caller dialing 9-1-1 is connected to an inappropriate PSAP, the dispatcher at that PSAP will be powerless to help the caller even if the caller's geographical location is known. Even though a dispatcher at an inappropriate PSAP may know where the caller is dialing from by means of dialogue with the caller, the dispatcher is nonetheless unable to directly send emergency services to that location because the location is outside the PSAP's geographical area of responsibility. In an emergency situation, response times are crucial, and any delay can mean the difference between life and death.
For PSTN telephones, ensuring the selection of an appropriate PSAP is straightforward. Because a traditional PSTN telephone is necessarily associated with a specific geographical location, a phone company can create a record associating that traditional PSTN telephone with an appropriate PSAP. Emergency calls from that traditional PSTN telephone will be routed, according to that record, to the corresponding PSAP.
For mobile phones, the Enhanced 911 (“E911”) system provides a standardized technological solution for routing emergency calls. When an emergency call is placed using a mobile phone with E911-compliant service, the phone's current location information is made available to the E911 system, which then selects an appropriate PSAP on the basis of that information. In practice, the location information is derived from Global Positioning System (“GPS”) data supplied by the phone itself, cell-tower triangulation, or a combination thereof. Though E911 is not infallible, it is a generally reliable solution for handling emergency calls from mobile phones.
The increasing adoption of Voice over Internet Protocol (“VoIP”) technology has introduced technological challenges beyond those currently addressed by E911. First, VoIP service is a so-called “over-the-top” (“OTT”) service. The term “OTT” refers to any service whose data is transmitted as general network traffic over a preexisting Internet connection. The OTT nature of VoIP service limits the ability of an initiating device to ascertain its own geographical location. In general, an initiating device, when making a call, is “aware” only of the fact that an underlying network connection is available. Accordingly, the initiating device is “ignorant” of additional information concerning the network connection that could otherwise be useful in determining its geographical location. Such additional information may, for example, include the identity and geographical location of the cell tower supplying the network connection.
Second, while methods have been developed for tracking the location of certain initiating devices through measures that operate independently of VoIP service (e.g., separately maintained location records), those methods are subject to technological constraints that limit the circumstances in which reliable location information can be obtained. Consequently, mobile devices (e.g., laptop computers) often offer no emergency calling at all.
Emergency calling through VoIP is further complicated when initiating devices can be associated with phone numbers from the public switched telephone network (“PSTN”), as is the case in business-oriented VoIP services (e.g., Skype for Business™). For businesses, the availability of PSTN phone numbers is often desirable because an initiating device can keep the same PSTN phone number regardless of its actual geographic location. This, however, may lead to misrouted emergency calls. Because the E911 system cannot reliably distinguish between an initiating device with a PSTN phone number and a “true” PSTN device (e.g., a traditional PSTN telephone or mobile phone), the E911 system may be unable to correctly identify the geographical location of an initiating device.
For consumer-grade VoIP services (e.g., consumer Skype® service), the difficulties are even greater. Because such services generally do not associate user accounts with PSTN phone numbers, PSTN caller-identification systems cannot provide meaningful identification concerning the origin of a call from a consumer-oriented VoIP service. In practice, the “origin number” of a call made from a consumer-oriented VoIP account may be an “unknown caller” indication, an arbitrary PSTN phone number with no relationship to the caller, or a series of digits that do not constitute a valid PSTN phone number (e.g., “000-000-0000”). If an emergency call is made from a consumer-oriented VoIP account, the E911 system will be unable to route the call to the appropriate PSAP.
Without a way to accurately determine the geographical origin of a VoIP-based emergency call, the call may be disconnected, routed to an incorrect PSAP, or routed to an inappropriate phone line within a PSAP (e.g., an administrative phone line, as opposed to a phone line connecting to 911 dispatchers).
VoIP services have generally addressed the problem of emergency calling by associating each initiating device with a registered location. As a practical matter, the registered location of an initiating device is usually defined in advance of using the device (e.g., immediately upon the activation of VoIP service). While a registered location can, in principle, be any location to which emergency services can be dispatched, a registered location is typically a home address (if the initiating device is for personal use) or an office address (if the initiating device is for business use). Emergency calling from the initiating device is enabled only when the device is confirmed to be present at its registered location. The registered location of a VoIP desk phone, for instance, may be the street address of the office building in which the phone is located. When an emergency call is placed from the phone, the location of the phone may be confirmed in various ways (e.g., by verifying that the phone is connected to a specific corporate network). If the confirmed location of the phone matches the registered location, the emergency call is allowed to proceed. Otherwise, the emergency call should be “blocked” (i.e., disconnected). The use of registered locations ensures that any initiating device that successfully places an emergency call is known to be present at a specific geographical location (i.e., the initiating device's registered location) to which emergency services should be dispatched.
The use of registered locations can be especially limiting for mobile devices (e.g., smartphones). By specifying a registered location from which a mobile device can place VoIP emergency calls, a registered location effectively forces the mobile device to function as a PSTN telephone for the purposes of emergency calling.
An additional source of complication is the pending adoption of text-based modes of communicating with emergency dispatchers (e.g., “Text-to-911” functionality). As a practical matter, many VoIP calling programs (e.g., Skype®) are capable of sending text messages. As in the case of an emergency call, emergency services cannot be dispatched in response to a text message unless the geographical origin of that text message can be determined.
Accordingly, there is a need for a system and method to allow initiating devices to request emergency services from any location an emergency call can be made or a text message requesting emergency services can be sent.